This invention relates in general to surgical instruments and in particular to an improved trocar assembly. Trocar assemblies are used in laparoscopic and other minimally invasive surgical procedures to puncture the abdominal wall and to form an opening or conduit therethrough. A physician can then perform the surgery through the relatively small opening which is held open by the trocar assembly. An inert gas is typically introduced into the abdominal cavity to expand the abdominal cavity. Surgical instruments or optical devices can then be inserted through a longitudinal bore formed through the trocar assembly for access to the expanded abdomen cavity.
Trocar assemblies typically include seals which generally prevent the inert gas from escaping from the abdominal cavity. The seals also permit the insertion of a shaft of an optical device or surgical instrument through the longitudinal bore of the trocar assembly while generally maintaining a seal during the insertion of the surgical instrument. Some trocar assemblies include multiple seals to allow for the sealing of surgical instruments having different shaft diameters which may be used throughout the operation. Typical shaft diameters are 5 mm, 10 mm, and 12 mm. To change to the desired sized seal, the surgeon is generally required to manipulate the trocar assembly in some manner so as to change the position of the seals until the desired sized seal is aligned with the longitudinal bore formed through the trocar assembly. For many of the trocar assemblies having multiple seals, it is often cumbersome for the surgeon to manipulate the trocar assembly to position the desired sized seal. These types of trocar assemblies typically require the use of both hands of the surgeon, which is generally undesirable. It is therefore desirable to have a trocar assembly which is easy to use and provides for sealing of inert gas from within the abdominal cavity while allowing for different surgical instrument shaft diameters to be inserted therethrough.